Area Forecast Discussion
Issued by NWS Sterling, VA

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000 FXUS61 KLWX 250140 AFDLWX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC 940 PM EDT FRI JUL 24 2015 .SYNOPSIS... HIGH PRESSURE REMAINS OVER THE REGION THROUGH SUNDAY. A WEAK COLD FRONT WILL SLIDE INTO THE AREA FROM THE NORTHWEST SUNDAY NIGHT AND MONDAY BEFORE DISSIPATING TUESDAY. ANOTHER COLD FRONT WILL APPROACH FROM THE NORTHWEST ON THURSDAY. && .NEAR TERM /THROUGH SATURDAY NIGHT/... SFC HIGH SLOWLY BUILDING EAST...WITH CENTER CURRENTLY MVG INTO WESTERN AREAS OF THE CWA. RIDGE AXIS STILL WELL WEST...OVER THE CENTRAL US...WHICH WILL CONTINUE TO BUILD AND BROADEN HEADING INTO THE WEEKEND. A SHORTWAVE...AS EVIDENT ON 01Z WATER VAPOR IMAGERY TRAVERSING THE GREAT LAKES WILL BRING INCREASED CLOUD COVER TONIGHT AS IT DIVES SE THRU THE MID ATLANTIC. PATCHY FOG WILL BE PSBL IN THE VALLEYS WITH WINDS OVERALL LIGHT AND VRB. OVERNIGHT SLIGHTLY WARMER THAN LAST NIGHT WITH THE CLOUD COVER. THE RDG WL BE ATOP US TMRW MRNG...BUT WL DRIFT E BY AFTN. THIS WL ENABLE A PINCH OF RETURN FLOW-- SUFFICIENT FOR DEWPTS TO BEGIN ITS CREEP UPWD. STILL NOT BAD FOR THIS TIME OF YR...LWR 60S. NAM ATTEMPTING TO DVLP DIURNALLY DRIVEN/OROGRAPHICALLY ENHANCED CNVCTN IN THE SW CORNER OF THE CWFA. AM NOT BUYING THAT SOLN ATTM...AS THERE IS NOTHING OTHER THAN THE TRRN TO PROVIDE FORCING...AND MID LVL TEMPS SHUD BE QUITE WARM. DO THINK THAT THERE WL BE MORE CLDS DVLPG...BUT STILL NOT ENUF TO PRECLUDE A MOSUN FCST. HV BROGUTH MAXT UP CLOSER TO 90F...BUT ASIDE FM DCA/DMH/EZF HV NOT TAKEN TEMPS ABV THAT LVL. SAT NGT WL BE QUIET AS WELL...W/ LGT SLY FLOW. HV GONE ON THE WARMER SIDE OF MOS IN RESPONSE...W/ MIN-T IN THE MID-UPR 60S FOR A GREATER PROPORTION OF THE AREA. && .SHORT TERM /SUNDAY THROUGH MONDAY/... HEIGHTS WILL GRADUALLY RISE SUNDAY AS A DEEP-LAYER RIDGE BUILDS OVER THE CENTRAL CONUS. EMBEDDED SHORTWAVES IN NORTHWEST FLOW ALOFT COUPLED WITH A SHARPENING SURFACE TROUGH/WEAK COLD FRONT APPROACHING FROM THE NORTHWEST SHOULD TRIGGER A FEW SCATTERED SHOWERS AND THUNDERSTORMS DURING THE AFTERNOON. SOUTHERLY FLOW AHEAD OF THE TROUGH AND WARM NOSE AT 850 MB WILL RESULT IN INCREASING HEAT/HUMIDITY DURING THE AFTERNOON. MODEL FORECAST SOUNDINGS SUGGEST MLCAPE OF 500-1000 J/KG BY LATE IN THE DAY BUT EFFECTIVE SHEAR REMAINS IN THE 20-25 KT RANGE. STILL...INVERTED-V PROFILES AND DCAPE APPROACHING 1000 J/KG ALONG WITH MODEST FORCING FROM UPPER-JET /65 KTS AROUND 250 MB/ COULD LEND TO BRIEF MULTI-CELLULAR ORGANIZATION WITH A FEW STRONG WIND GUSTS POSSIBLE. THE WEAK COLD FRONT STALLS OVER THE EASTERN THIRD OF THE CWA LATE SUNDAY NIGHT INTO MONDAY. 850 TEMPS MONDAY A COUPLE DEGREES COOLER WITH MORE CLOUDS AROUND AND THAT SHOULD RESULT IN SURFACE TEMPS A FEW DEGREES LOWER THAN ON SUNDAY. NO REAL CHANGE IN DEW POINTS THOUGH AS FLOW REMAINS LIGHT AND VARIABLE OR EVEN EASTERLY FOR A BRIEF TIME MONDAY AS A WEAK WAVE OF LOW PRESSURE DEVELOPS TO THE SOUTH OVER THE CAROLINAS. && .LONG TERM /MONDAY NIGHT THROUGH FRIDAY/... WEAKENING FRONT/SFC TROUGH REMAINS IN THE AREA MON NIGHT INTO TUE. SOME SHOWERS AND TSTMS ARE PSBL AS THIS BOUNDARY WEAKENS DURING THIS PERIOD. HIGH PRES BRIEFLY BUILDS OVER OVER OUR REGION WED INTO THU BRINGING DRIER CONDITIONS. COLD FRONT APPROACHES FROM THE NW LATE ON THU AND MOVE ACROSS OUR CWA ON FRI... BRINGING SHOWERS AND TSTMS TO THE REGION. HIGH TEMPS WILL BE NEAR NORMAL TUE AND WARMING UP INTO THE 90S ON THU... AND BACK TO NEAR NORMAL FRI. && .AVIATION /02Z SATURDAY THROUGH WEDNESDAY/... VFR CONDITIONS FOR THE TAF PERIOD. LIGHT FLOW...WITH WINDS GENERALLY 5 KTS OR LESS THRU 21Z SAT. SLIGHT INCREASE AFTR 21Z...WITH SLY FLOW 8-10 KTS PSBL HEADING INTO SAT NIGHT. MAINLY VFR EXPECTED SUN-MON. SLY WINDS GENERALLY 10 KT OR LESS. VFR CONDITIONS EXPECTED MOST OF THE TIME MON NIGHT INTO TUE. SUB- VFR CONDITIONS PSBL DUE TO SCATTERED SHOWERS AND TSTMS. && .MARINE... SUB-SCA CONDITIONS TONIGHT THRU SAT AFTN. PSBL SLY CHANNELING LATER SAT COULD RESULT IN OCNL GUSTS TO SCA LVLS. HOWEVER...VERY MARGINAL THREAT ATTM...AND CONFIDENCE NOT ENOUGH TO ISSUE SCA. SOUTHERLY CHANNELING AHEAD OF A SHARPENING SURFACE TROUGH/WEAK COLD FRONT WILL LIKELY RESULT IN SCA GUSTS FOR PORTIONS OF THE WATERS SUNDAY AFTERNOON INTO SUNDAY EVENING. AS THE FRONT STALLS OVER THE AREA INTO MONDAY...GUSTS SHOULD SUBSIDE. SUB-SCA CONDITIONS EXPECTED FOR MON NIGHT INTO TUE. PSBL SHOWERS AND TSTMS OVER THE WATERS DURING THIS PERIOD. && .TIDES/COASTAL FLOODING... SOUTHERLY FLOW INCREASES SUNDAY INTO MONDAY. THIS WILL PUSH TIDAL ANAMOLIES UP ENOUGH TO APPROACH MINOR FLOOD NEAR TIMES OF HIGH TIDE AT MOST VULNERABLE LOCATIONS STARTING WITH SUNDAY EVENING`S HIGH TIDE CYCLE...LASTING INTO MONDAY. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...NONE. MD...NONE. VA...NONE. WV...NONE. MARINE...NONE. && $$ SYNOPSIS...HTS/SEARS NEAR TERM...SEARS/HTS SHORT TERM...DFH LONG TERM...IMR AVIATION...SEARS/IMR/DFH MARINE...SEARS/IMR/DFH TIDES/COASTAL FLOODING...

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